ISHS Acta Horticulturae 387: III International Protea Research Symposium
COMMERCIAL PICKING OF BANKSIA HOOKERIANA FROM NATURAL POPULATIONS ADVERSELY AFFECTS SHOOT, FLOWER AND SEED PRODUCTION AND PLANT NUTRIENT STATUS |
| Authors: | E.T.F. Witkowski, Byron B. Lamont |
| Abstract:
The impact of bloom picking on subsequent flower and cone production, seed bank dynamics and plant architecture were studied in three picked and three unpicked populations of Banksia hookeriana near Eneabba, Western Australia. Losses of dry mass and mineral nutrients, via commercial bloom picking and flower head removal by cockatoos were quantified. A total of 13 255 blooms were picked ha-1 over the last 9 years, or 29% of production. Cockatoos removed a further 2 477 flower heads.ha-1 (5%). Picking reduced plant canopy volume by 44% and the number of 1 year old stems by 56%. Picked plants produced 35% fewer blooms, while seed production and storage were reduced by 50% and 57% respectively. Aerial dry mass and N and P contents were reduced by 20.3%, 29.8% and 31.3%, respectively, whereas cockatoos removed only 1.1%, 1.3% and 1.7% during the same period. Ecosystem losses of N and P at 3103 g N.ha-1 and 152 g P.ha-1 since the last fire were substantial, but losses from cockatoo damage were virtually negligible. The reduced seed store with picking may adversely affect post-fire regeneration, especially in the event of a short fire interval. Sink (inflorescence) removal reduced the nutrient status of the plant, especially in terms of N, due largely to the loss of nutrients and energy stored in the recently mature leaves supported on the picked stem. | |
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